setup-go should install non-git VCS binaries

My project has a transitive test dependency on a bzr repo or two. It’s been a continual source of annoyance, and I haven’t been able to find a workaround so that developers can just use Go out of the box without installing bzr.

After invoking setup-go, and calling a go run command, I see the following error:

  > [line 0 : column 0] - loading files from package ".": go [list -f {{context.GOARCH}} {{context.Compiler}} -- unsafe]: exit status 1: go: labix.org/v2/mgo@v0.0.0-20140701140051-000000000287: bzr branch --use-existing-dir https://launchpad.net/mgo/v2 . in /home/runner/go/pkg/mod/cache/vcs/ca61c737a32b1e09a0919e15375f9c2b6aa09860cc097f1333b3c3d29e040ea8: exec: "bzr": executable file not found in $PATH
 go: launchpad.net/gocheck@v0.0.0-20140225173054-000000000087: bzr branch --use-existing-dir https://launchpad.net/~niemeyer/gocheck/trunk . in /home/runner/go/pkg/mod/cache/vcs/f46ce2ae80d31f9b0a29099baa203e3b6d269dace4e5357a2cf74bd109e13339: exec: "bzr": executable file not found in $PATH
go: error loading module requirements

Specifically, the exec: "bzr": executable file not found in $PATH piece indicates that bzr is unavailable.

According to go help importpath on go 1.12:

The vcs is one of “bzr”, “fossil”, “git”, “hg”, “svn”.

I don’t have any dependencies on fossil, hg, or svn, so I don’t know whether they’re available.

My redacted workflow file looks like:

on: push

jobs:
  analyze:
    name: analyze
    runs-on: ubuntu-latest
    steps:

    - name: Set up Go 1.12
      uses: actions/setup-go@v1
      with:
        go-version: 1.12
      id: go

    - name: Check out code
      uses: actions/checkout@v1

    - name: Build and run analyzer
      run: GO111MODULE=on go run example.com/analyzer ./...

[kjk]

If you use Go 1.12+ and modules you can use module proxy. Set GOPROXY env variable to https://proxy.golang.org. On 1.13 you don’t even have to do that as it’s the default.

Here’s a full example: https://onepage.nopub.io/p/Using-GitHub-Actions-with-Go-2ca9744b531f4f21bdae9976d1ccbb58#49a308c7-e5de-4c3d-85f0-c319464a0969

When using module proxy, go tool doesn’t uses git or bzr to get the modules your project depends on but gets them from a caching proxy.

[bryanmacfarlane]

I don’t think this should be the responsibility of this action. This action is responsible for pulling go install pkg, adding it to the path and setting up problem matchers. I also agree with @kjk